John R. W. Kestle, Hugh J. L. Garton, William E. Whitehead, James M. Drake, Abhaya V. Kulkarni, D. Douglas Cochrane, Cheryl Muszynski and Marion L. Walker
Approximately 10% of cerebrospinal fluid (CSF) shunt operations are associated with infection and require removal or externalization of the shunt, in-hospital treatment with antibiotic agents, and insertion of a new shunt. In a previous survey, the authors identified substantial variation in the duration of antibiotic therapy as well as the duration of hospital stay. The present multicenter pilot study was undertaken to evaluate current strategies in the treatment of shunt infection.
Patients were enrolled in the study if they had a successful treatment of a CSF shunt infection proved by culture of a CSF specimen. Details of their care and the incidence of culture-proved reinfection were recorded.
Seventy patients from 10 centers were followed up for 1 year after their CSF shunt infection. The initial management of the infection was shunt externalization in 17 patients, shunt removal and external ventricular drain insertion in 50, and antibiotic treatment alone in three. Reinfection occurred in 18 patients (26%). Twelve of the 18 reinfections were caused by the same organism and six were due to new organisms. The treatment time varied from 4 to 47 days, with a mean of 17.4 days for those who later experienced a reinfection compared with 16.2 days for those who did not. The most common organism (Staphylococcus epidermidis, 34 patients) was associated with a reinfection rate of 29% and a mean treatment time of 12.8 days for those who suffered reinfection and 12.5 days for those who did not.
Reinfection after treatment of a CSF shunt infection is alarmingly common. According to the data available, the incidence of reinfection does not appear to be related to the duration of antibiotic therapy.
Jennifer Strahle, Ndi Geh, Béla J. Selzer, Regina Bower, Mai Himedan, MaryKathryn Strahle, Nicholas M. Wetjen, Karin M. Muraszko, Hugh J. L. Garton and Cormac O. Maher
There is currently no consensus on the safety of sports participation for patients with Chiari I malformation (CM-I). The authors' goal was to define the risk of sports participation for children with the imaging finding of CM-I.
A prospective survey was administered to 503 CM-I patients at 2 sites over a 46-month period. Data were gathered on imaging characteristics, treatment, sports participation, and any sport-related injuries. Additionally, 81 patients completed at least 1 subsequent survey following their initial entry into the registry and were included in a prospective group, with a mean prospective follow-up period of 11 months.
Of the 503 CM-I patients, 328 participated in sports for a cumulative duration of 4641 seasons; 205 of these patients participated in contact sports. There were no serious or catastrophic neurological injuries. One patient had temporary extremity paresthesias that resolved within hours, and this was not definitely considered to be related to the CM-I. In the prospective cohort, there were no permanent neurological injuries.
No permanent or catastrophic neurological injuries were observed in CM-I patients participating in athletic activities. The authors believe that the risk of such injuries is low and that, in most cases, sports participation by children with CM-I is safe.
Kyle T. Johnson, Wajd N. Al-Holou, Richard C. E. Anderson, Thomas J. Wilson, Tejas Karnati, Mohannad Ibrahim, Hugh J. L. Garton and Cormac O. Maher
Our understanding of pediatric cervical spine development remains incomplete. The purpose of this analysis was to quantitatively define cervical spine growth in a population of children with normal CT scans.
A total of 1458 children older than 1 year and younger than 18 years of age who had undergone a cervical spine CT scan at the authors' institution were identified. Subjects were separated by sex and age (in years) into 34 groups. Following this assignment, subjects within each group were randomly selected for inclusion until a target of 15 subjects in each group had been measured. Linear measurements were performed on the midsagittal image of the cervical spine. Twenty-three unique measurements were obtained for each subject.
Data showed that normal vertical growth of the pediatric cervical spine continues up to 18 years of age in boys and 14 years of age in girls. Approximately 75% of the vertical growth occurs throughout the subaxial spine and 25% occurs across the craniovertebral region. The C-2 body is the largest single-segment contributor to vertical growth, but the subaxial vertebral bodies and disc spaces also contribute. Overall vertical growth of the cervical spine throughout childhood is dependent on individual vertebral body growth as well as vertical growth of the disc spaces. The majority of spinal canal diameter growth occurs by 4 years of age.
The authors' morphometric analyses establish parameters for normal pediatric cervical spine growth up to 18 years of age. These data should be considered when evaluating children for potential surgical intervention and provide a basis of comparison for studies investigating the effects of cervical spine instrumentation and fusion on subsequent growth.
Wajd N. Al-Holou, Thomas M. O'Lynnger, Aditya S. Pandey, Joseph J. Gemmete, B. Gregory Thompson, Karin M. Muraszko, Hugh J. L. Garton and Cormac O. Maher
This study was undertaken to define the age-related prevalence of cavernous malformations (CMs) in children and young adults undergoing intracranial imaging. In addition, the authors aim to clarify the natural history of CMs in young people, especially in those with incidentally discovered lesions.
To identify those patients with CMs, the authors retrospectively reviewed the electronic medical records of 14,936 consecutive patients 25 years of age or younger who had undergone brain MR imaging. In patients with a CM, clinical and imaging data were collected. Patients with untreated cavernomas who had more than 6 months of clinical and MR imaging follow-up were included in a natural history analysis. The natural history analysis included 110 CMs in 56 patients with a 3.5-year mean clinical follow-up interval (199 patient-years and 361 cavernoma-years).
In 92 patients (0.6%), 164 CMs were identified. The imaging prevalence of cavernomas increased with advancing age (p = 0.002). Multiple CMs occurred in 28 patients (30%), and 8 patients (9%) had a family history of multiple CMs. Fifty patients (54%) presented with symptoms related to the cavernoma, of whom 30 presented with hemorrhage (33%). Of the 164 cavernomas identified, 103 (63%) were considered incidental, asymptomatic lesions. Larger size was associated with acute symptomatic presentation (p = 0.0001). During the follow-up interval, 6 patients with 8 cavernomas developed 11 symptomatic hemorrhages after initial identification. Five of the patients who had a hemorrhage during the follow-up interval had initially presented with hemorrhage, while only 1 had presented incidentally. The hemorrhage rate for all patients in the natural history group was 1.6% per patient-year and 0.9% per cavernoma-year. The hemorrhage rate was 8.0% per patient-year in the symptomatic group versus 0.2% in the incidental group. Symptomatic hemorrhage after long-term follow-up was associated with initial acute presentation (p = 0.02).
The imaging prevalence of CM increases with advancing age during childhood. Patients presenting without hemorrhage have a significantly lower risk of bleeding compared with those who present with acute neurological symptoms. Comparing this series of children to prior analyses of CM natural history in adults, the authors' data do not suggest a higher bleeding risk in younger patients.
Wajd N. Al-Holou, Samuel W. Terman, Craig Kilburg, Hugh J. L. Garton, Karin M. Muraszko, William F. Chandler, Mohannad Ibrahim and Cormac O. Maher
We reviewed our experience with pineal cysts to define the natural history and clinical relevance of this common intracranial finding.
The study population consisted of 48,417 consecutive patients who underwent brain MR imaging at a single institution over a 12-year interval and who were over 18 years of age at the time of imaging. Patient characteristics, including demographic data and other intracranial diagnoses, were collected from cases involving patients with a pineal cyst. We then identified all patients with pineal cysts who had been clinically evaluated at our institution and who had at least 6 months of clinical and imaging follow-up. All inclusion criteria for the natural history analysis were met in 151 patients.
Pineal cysts measuring 5 mm or larger in greatest dimension were found in 478 patients (1.0%). Of these, 162 patients were male and 316 were female. On follow-up MR imaging of 151 patients with pineal cyst at a mean interval of 3.4 years from the initial study, 124 pineal cysts remained stable, 4 increased in size, and 23 decreased in size. Cysts that were larger at the time of initial diagnosis were more likely to decrease in size over the follow-up interval (p = 0.004). Patient sex, patient age at diagnosis, and the presence of septations within the cyst were not significantly associated with cyst change on follow-up.
Follow-up imaging and neurosurgical evaluation are not mandatory for adults with asymptomatic pineal cysts.
Jayapalli Rajiv Bapuraj, Amy K. Bruzek, Jamaal K. Tarpeh, Lindsey Pelissier, Hugh J. L. Garton, Richard C. E. Anderson, Bin Nan, Tianwen Ma and Cormac O. Maher
Current understanding of how the pediatric craniocervical junction develops remains incomplete. Measurements of anatomical relationships at the craniocervical junction can influence clinical and surgical decision-making. The purpose of this analysis was to quantitatively define clinically relevant craniocervical junction measurements in a population of children with CT scans that show normal anatomy.
A total of 1458 eligible patients were identified from children between 1 and 18 years of age who underwent cervical spine CT scanning at a single institution. Patients were separated by both sex and age in years into 34 groups. Following this, patients within each group were randomly selected for inclusion until a target of 15 patients in each group had been reached. Each patient underwent measurement of the occipital condyle–C1 interval (CCI), pB–C2, atlantodental interval (ADI), basion-dens interval (BDI), basion-opisthion diameter (BOD), basion-axial interval (BAI), dens angulation, and canal diameter at C1. Mean values were calculated in each group. Each measurement was performed by two teams and compared for intraclass correlation coefficient (ICC).
The data showed that CCI, ADI, BDI, and dens angulation decrease in magnitude throughout childhood, while pB–C2, PADI, BAI, and BOD increase throughout childhood, with an ICC of fair to good (range 0.413–0.912). Notably, CCI decreases continuously on coronal CT scans, whereas on parasagittal CT scans, CCI does not decrease until after age 9, when it shows a continuous decline similar to measurements on coronal CT scans.
These morphometric analyses establish parameters for normal pediatric craniocervical spine growth for each year of life up to 18 years. The data should be considered when evaluating children for potential surgical intervention.
Siri Sahib S. Khalsa, Ndi Geh, Bryn A. Martin, Philip A. Allen, Jennifer Strahle, Francis Loth, Desale Habtzghi, Aintzane Urbizu Serrano, Daniel McQuaide, Hugh J. L. Garton, Karin M. Muraszko and Cormac O. Maher
Chiari malformation Type I (CM-I) is typically defined on imaging by a cerebellar tonsil position ≥ 5 mm below the foramen magnum. Low cerebellar tonsil position is a frequent incidental finding on brain or cervical spine imaging, even in asymptomatic individuals. Nonspecific symptoms (e.g., headache and neck pain) are common in those with low tonsil position as well as in those with normal tonsil position, leading to uncertainty regarding appropriate management for many patients with low tonsil position and nonspecific symptoms. Because cerebellar tonsil position is not strictly correlated with the presence of typical CM-I symptoms, the authors sought to determine if other 2D morphometric or 3D volumetric measurements on MRI could distinguish between patients with asymptomatic and symptomatic CM-I.
The authors retrospectively analyzed records of 102 pediatric patients whose records were in the University of Michigan clinical CM-I database. All patients in this database had cerebellar tonsil position ≥ 5 mm below the foramen magnum. Fifty-one symptomatic and 51 asymptomatic patients were matched for age at diagnosis, sex, tonsil position, and tonsil morphology. National Institutes of Health ImageJ software was used to obtain six 2D anatomical MRI measurements, and a semiautomated segmentation tool was used to obtain four 3D volumetric measurements of the posterior fossa and CSF subvolumes on MRI.
No significant differences were observed between patients with symptomatic and asymptomatic CM-I related to tentorium length (50.3 vs 51.0 mm; p = 0.537), supraoccipital length (39.4 vs 42.6 mm; p = 0.055), clivus-tentorium distance (52.0 vs 52.1 mm; p = 0.964), clivus-torcula distance (81.5 vs 83.3 mm; p = 0.257), total posterior fossa volume (PFV; 183.4 vs 190.6 ml; p = 0.250), caudal PFV (152.5 vs 159.8 ml; p = 0.256), fourth ventricle volume to caudal PFV ratio (0.0140 vs 0.0136; p = 0.649), or CSF volume to caudal PFV ratio (0.071 vs 0.061; p = 0.138).
No clinically useful 2D or 3D measurements were identified that could reliably distinguish pediatric patients with symptoms attributable to CM-I from those with asymptomatic CM-I.